Although much new information about normal and abnormal esophageal motor function has been gathered during the past decade, many important questions remain unanswered. This grant proposal represents a broad-fronted approach to investigating esophageal motor function in normal human subjects, patients with reflux esophagitis, patients with a variety of esophageal motility disorders, and in laboratory animals. The specific study projects fall into four general categories: (1) Instrumentation and technique for esophageal pressure recording, (2) Reflux esophagitis and hiatal hernia, (3) Esophageal motor physiology in normal subjects and experimental animals, and (4) Studies of miscellaneous motility disorders, such as, achalasia, scleroderma, and Zenker's diverticulum. An important part of the study is to further refine the instrumentation and methodology for accurately recording esophageal pressure events. Achievement of high-fidelity recording is a necessary corner stone for meaningful future investigative studies of esophageal motor activity. A second major area of emphasis in this proposal is the pathophysiology and treatment of reflux esophagitis. We believe the development of reflux esophagitis is governed by several factors including: competency of the antireflux mechanism, potency of reflux material, efficiency of esophageal clearing mechanism, and resistance of the esophageal tissues. Studies have been designed to further investigate the antireflux mechanism and the efficacy of esophageal clearing in patients with reflux esophagitis and control subjects. Plans also include follow-up studies on the efficacy of the Nissen and Belsey Mark IV surgical procedures in the treatment of reflux esophagitis. Studies in normal human subjects and experimental animals are designed to evaluate factors governing esophageal bolus transport and the neural control mechanism of esophageal motor function.